My 4 year old dog is going to the bathroom in the house. We lived with my parents and their dog urinated in the house so my dog would mark his territory wherever the other dog went. He also used to go on pads at night based on our vet recommending this. Friends have said this is his way of getting back at me for moving to a new home. I'm getting frustrated and now I have a baby on the way so I don't want him doing this anymore. Please help me!

I have a Cocker Spaniel who is 4 years old, I was previously living with my parents who had other animals and another dog that used to urinate in the house. So of course my dog would go and "mark his territory" where the other dog went. My dog is trained to go outside and also use pads, our vet recommended the pads because Cocker Spaniels drink a lot of water and if they need to go at night, they can. When living with my parents he used the pad at night when he had to until my boyfriend came, but now that I moved, he has been doing both 1 and 2 in the house. I walk him in the mornings. I let him out all the time, but I don't know how to get him to stop. Friends said that it could be his way of getting back at us for moving him away from the other animals, or the fact that where we moved to they had another dog that used to go to the bathroom as well. I'm getting very frustrated considering I have a baby on the way and don't want him going to the bathroom in the house anymore. Please help me!!